Apple has formally acknowledged an iMessage bug that prevents former iOS users from receiving SMS messages on non-iOS devices, and has promised a fix in a fresh update

Apple has acknowledge an iMessage design flaw that prevents former iOS users from receiving SMS messages when they leave the ecosystem and forget to disable iMessage before doing so.

The iMessage problem is caused when iOS users switch over to a different ecosystem — such as Google’s Android operating system — without turning the iMessage service off first. The problem stems from the ability of iMessage to send messages via Wi-Fi and Apple servers rather than as a standard SMS sent via a wireless carrier. It saves users network costs but causes the bug due to confusing miscommunication in the software if iMessage is left operational and a phone number is still recognized as linked to an iPhone.

Texts to these users from other devices are therefore never delivered, and are left floating in the iMessage cloud instead, as the iMessage protocol is still used for numbers no longer linked to an iPhone.

In a statement to Re/code, the iPad and iPhone maker commented:

We recently fixed a server-side iMessage bug which was causing an issue for some users, and we have an additional bug fix in a future software update. For users still experiencing an issue, please contact AppleCare.

This is the company’s first official response to the flaw, which has existed since iOS 5 when the messaging app was first rolled out. A fix was released after the launch of iOS 7, but the problem is still leaving users in “iMessage purgatory,” according to comments made to former chief editor of Lifehacker Adam Pash by Apple support staff.

According to the publication, a recent server glitch made the problem worse, as AppleCare representatives were left unable to remedy the issue for customers impacted by the iMessage flaw.

The protocol problem has gone far enough to warrant legal action. This month at a Californian district court, Adrienne Moore claimed that Apple “interfered” with cellular contracts by preventing subscribers from receiving SMS messages, after Moore switched from an iPhone 4 to a Galaxy S5. Moore claims that Apple’s message interception prevents users from enjoying a full wireless carrier service after they’ve made a switch from an iPhone to another device.